The two leading contenders seems to be that it is A) an old whale placenta or B) a rare and enigmatic deep-sea jellyfish.  And the answer is…. B)

A) So why is not an old whale placenta?  The video is from approximately 5000 feet (1500 m). A placenta would need to sink to this depth without any other organism consuming it.  Unlikely given that its rate of decent would have been slow and any organic food source in the deep sea is unlikely to last long.

B) So why is it a jellyfish?* In 1967, F.S. Russell described a very enigmatic deep-sea jellyfish, Deepstaria enigmatica.

During Dive 159 of the U.S. research submersible Deepstar 400 on 22 October 1966 Dr. Eric G. Barham, Dr. George Pickwell, and Mr. Ronald Church collected a remarkable scyphomedusan at a depth of about 723 m in the San Diego Trough…when first noted, the jellyfish’s margin was collapsed and the [outer, convex surface of the umbrella] indented.

In other words it didn’t look like much of a jellyfish.  Sound familiar?

On opposite sides of the umbrella are two large tubular shaped processes…It has a yellowish brown tinge…The radial canal system is most striking.  It consists of a meshwork, likened by Dr. Barham to wire-netting.

The gonads are situated along the margins of fan-shape mesenteries, and tend to be broken up into several isolated processes with incurved edges.

In 1988 Larson and colleagues published further work describing this rare group of jellyfish.  They too noted the unique canal system.

But it is these researcher’s behavioral notes that I find most interesting.

These two species of Deepstaria display some unique behaviour; peristaltic locomotion and pursing of the bell margin are unknown in other medusae. Probably the peristaltic locomotion is necessary because the umbrella is too thin and the subumbrella musculature too diffuse to support more rapid pulsation. Our observations of both species of Deepstaria suggest that they usually hang  motionless with the umbrella open…It seems probable to us that medusae in this genus are large ambush predators in the meso- and bathypelagic environment…we speculate that the feeding behaviour might be as follows. The medusae usually hang vertically and motionless with the bell open; occasional peristaltic contractions probably enable them to swim slowly, at least enough to retard sinking. Because the area of the subumbrella is so large, upward-swimming prey occasionally would swim into it. Once prey enter the large subumbrellar chamber, the contact stimulates rapid contraction of the coronal muscle, pursing the umbrella shut and trapping the prey. As the prey attempts to escape, it contacts nematocysts on the subumbrella, being repeatedly stung until weakened. It may additionally become covered with mucus and further immobilized. Then peristalsis and ciliary movement could transport the prey towards the mouth where the oral arms could grasp and engulf it…’Bagging’ prey in this way is not known in other medusae.

Russell, F. S. (1967). “On a remarkable new scyphomedusan Deepstaria enigmatica”. Journal of the Marine Biological Association of the UK 47: 469-473.

Larson, R.; Madin L., Harbison, G. (1988). “In situ observations of deep water medusae of the genus Deepstaria, with a description of D. reticulum sp. nov.”. Journal of the Marine Biological Association of the UK 68: 689-699.

*UPDATE: This has now also been confirmed by Dr. Steven Haddock of the Monterey Bay Aquarium Research Center, an expert on deep-sea and pelagic creatures.

UPDATE2: Steven Haddock provides some much better photos of Deepstaria engimatica on the Jellyfish Watch Facebook page.

UPDATE3: Several comments below suggest the species is Deepstaria reticulum.  Important thing is that it is still a jellyfish and already known.

The post Solving the Mystery of the Placental Jellyfish first appeared on Deep Sea News.

Much of the earth’s biodiversity lies within the phylum Arthropoda.  You are probably aware of many species within the group trilobites, spiders, centipedes, crabs, insects, lobsters, and whole other mélange of strange beasties.  Throw a crab and you are likely to hit another arthropod.  Scratch that as I cannot condone the throwing of  an exoskeletonized invertebrate simply for the sake of making a point.

The phylum Arthropoda can be subdivided into 5 subphyla.

1. Trilobitomorpha (the extinct trilobites)
2. Chelicerata (spiders, scorpions, horseshoe crabs, sea spiders, and the extinct sea scorpions)
3. Myriapoda (centipedes and millipedes)
4. Hexapoda (insects)
5. Crustacea (copepods, crabs, lobsters, shrimps, etc.)

Focusing in on Chelicerates you might notice they include the “sea spiders”.  But casting the seemingly spider-like appearances aside, the long legged  1300 species of Pycnogonida are not anything like arachnids and far more interesting.

• Pycnogonids can range in size from less than the size of penny to near three feet in length, the diameter of small coffee table, with the largest species occurring in the Antarctic and the deep sea.
• With thin legs and a small main body, no respiratory system or organs are needed.  Simple diffusion across the surface of the body is sufficient.  They however do possess a Buddha-like nature and obtain enlightenment in 2.3 years.
• The digestive tract extends into the legs and the gonads occur in the toes.  Foot fetishes are not considered a fetish among pycnogonids.
• Because of thinness of the legs, despite their length, muscles consist of only a single cell and often get lonely
• Males take care of the young.  Females are often deadbeats and get their wages garnished for child support.
• Pycnogonids feed on sessile (=non-moving) animals like barnacles, hydroids and corals. The literally suck out the life juices, and potentially the soul, from their prey with a long proboscis.

You can read up on a recent study at Science and catch a slide show to boot.  Kevin pontificates on why they are the sixth coolest species.  I discuss why they get so damn big.  You can also see classic illustrations from the Challenger expedition.

The post Pycnogonids, more than spiders of the sea first appeared on Deep Sea News.

Let’s start off “sex week” with the steamy sex life that fuels reproduction within Phylum Porifera, the sponges.  Part of the intrigue of sponge reproduction is that it is still mysterious—very few studies have been done.  Many sponges are hermaphroditic, others never change sexes in their whole life.  Still others alternate once or many times between being male and female.

Most research on sponge reproduction has been done on shallow-water sponges, with only inferences drawn for deep-sea sponges.  Unlike every other animal, sponges don’t have organized gonads.  Instead, sperm are produced in and float around in the sponge’s innards (called the mesohyl).  Sperm billow from excurrent canals like smoke coming from chimneys, coating the nearby surroundings in sponge unmentionables.  “Smoking sponges” can be triggered one at a time or in whole sleezes* of sponges (see video below).  Sperm release may happen many times throughout the year or in one massive discharge one night when the moon is right.  When sperm is pumped inside the feeding chambers of another sponge, if you know what I mean, the feeding cells in the chamber transform into sperm transport cells.  The sperm is packaged up and is brought to fertilize an oocyte.  After fertilization, sponge larvae are released into the water and either drift to a new location, or for glass sponges, drift or crawl to a new place to grow up.

Just in case sex isn’t enough, sponges can reproduce asexually as well.  Stick a sponge in a blender and you’ll end up with thousands.  Some sponges bud new offspring, while others produce cyst-like structures that withstand harsh conditions.  The saucy exploits of sponge sex have already introduced you to sleezy topics and smoking sponges—and this is just the beginning of sex week!

*Like a crash of rhinos or a gaggle of geese, an aggregation of sponges has its own collective name: a sleeze.  About one person in the world knows of this term: the student who coined it in 1978.  The term hasn’t caught on yet, but only because the details of sponge sex are not yet common knowledge.

The post “Sleezy” sponge sexuality first appeared on Deep Sea News.